Suicide is a significant public health problem among American college students.1-4 Suicidal college students tend not to seek help in their time of crisis, and when they do seek help they overwhelmingly turn to peers (i.e., friends, roommates, intimate partners).1,5,6 Peers respond in different ways, such as talking with the suicidal peer alone, telling a trusted adult (such as a teacher or resident advisor), advising the peer to seek help, or ignoring the situation.1,5,7 There is currently little understanding of how college students experience a suicidal peer or the factors that predict prosocial helping behavior toward a suicidal peer. This mixed-methods study will use a prosocial helping behavior model to overcome this limitation and will meet the following two research aims: (1) qualitatively understand how undergraduate college students experience a suicidal peer and (2) quantitatively identifying the factors that predict helping behavior toward a suicidal peer. Qualitative interviews will be conducted among college students with prior experience with a suicidal peer and quantitative surveys will be administered to college students regardless of prior experience. In both qualitative and quantitative arms of this study situational, bystander, victim, arousal, decisional balance and behavioral characteristics will be explored. PUBLIC HEALTH RELEVANCE: This study meets Healthy People 2020's call for a reduction in the national suicide rate and number of suicide attempts among adolescents8 because the factors found to predict prosocial helping behavior among college students towards suicidal peers could be targeted in preexisting and widely used gatekeeper suicide prevention training.9 This could then result in more college students acting as prosocial bystanders who encourage their suicidal peers to seek, which could reduce attempted and completed suicides within this at-risk population.